This application claims the priority of German patent document 10 2004 030 705.9, filed Jun. 25, 2004 (International Application No. PCT/EP2005/006613, filed Jun. 18, 2005), the disclosure of which is expressly incorporated by reference herein.
The invention relates to an air supply mechanism for a vehicle seat and to a method for the operation thereof.
German patent document DE 102 26 008 A1 discloses an air supply mechanism for a vehicle seat of an open vehicle having at least one air discharging opening that is provided in the upper region of the vehicle seat and via which the head, shoulder and neck region of the seat occupant can be subjected to an air flow in order to reduce undesirable draft phenomena. The air flow can be regulated by means of a control device and, when the air supply mechanism is switched on, the air flow is set to a basic value as a function of an automatically detected external parameter value such as, for example, an external temperature, or a specified value which can be selected by the seat occupant. After the basis value is set, further setting of the air flow takes place as a function of an automatically detected further parameter value, for example, the driving speed. The two parameter values serve to set a low, average or high basic value of the air flow, such that the basic value is determined by an assigned blower speed of the fan and an assigned heating power of the heating element. Based on this basic value, the air flow is set as a function of the driving speed in such a manner that, as the driving speed increases (decreases), the air flow and therefore the blower speed and the heating power of the heating element are increased (decreased).
However, in the case of the above-described conventional vehicle seat with seat heating system and ventilation device (air supply mechanism), there is the problem that, immediately after the air supply mechanism is switched on and the seat heating system and ventilation device are activated relatively cool air arrives at the shoulder and neck region of the seat occupant, since the heating element is not yet at the full heating power. This results in the seat occupant experiencing a draft and therefore leads to a loss of comfort.
Furthermore, German patent document DE 198 42 979 C1 discloses a vehicle seat with seat heating system and ventilation device in which, each time the seat heating system is switched on, the control unit simultaneously activates the ventilation device for a defined period of time after the seat heating system is switched on. In this case, the seat heating system and the ventilation device are switched on at full power, and the power of the ventilation device is reduced asymptotically to a predetermined final value within a period of time. This final value can either be zero or a value predetermined manually depending on the sensation of heat. This results in a specific combination of seat heating and seat ventilation in the heating-up phase of the vehicle seat causing the rate at which the cushion heats up in comparison to just the heating of the seat to be doubled. The seat heating system comprises a plurality of electric heating wires that are laid in an upholstery padding of the cushion. The ventilation device has a plurality of miniature fans which are arranged in air ducts integrated in the cushion and draw air from the vehicle interior region located below the vehicle seat and blow it into a ventilation layer of the cushion located below the upholstery padding.
German patent document DE 197 03 516 C1 discloses a vehicle seat with seat heating system and ventilation device in which the control unit is connected on the input side to a temperature sensor arranged in the cushion, and on the output side to the seat heating system and the ventilation device. The ventilation device has a plurality of miniature fans that are integrated in a cushion pad, draw air from the vehicle interior region located below the vehicle seat and blow it into a ventilation layer that covers the cushion pad. The ventilation layer is composed of a spacer knit. The seat heating system comprises a plurality of heating coils that are in each case assigned to a miniature fan and are arranged together with the latter in a respective air duct formed in the cushion pad. The control unit drives the ventilation device and the seat heating system in various combinations of fan and heating stages as a function of a current cushion temperature and a predetermined desired cushion temperature.
In the case of a vehicle seat that is disclosed in German patent document DE 199 53 385 A1, which includes a seat heating system and ventilation device, an operating device is provided for the manual actuation of the seat heating system and of the ventilation device. If the ventilation device is switched on manually, the control unit regulates the seat heating system automatically as a function of the temperature of the seat surface. The ventilation device and the seat heating system can be switched in a stepwise manner and/or continuously by the operating device. Regulation takes place within the defined limits set by the occupant via the operating device. In order to prevent supercooling by the ventilation device, when the ventilation device is switched on, the heating device for heating the vehicle seat is regulated automatically as a function of the seat surface temperature.
Also in these conventional vehicle seats having a seat heating system and ventilation device, because the heating element is not yet at the full heating power when the seat heating system and ventilation device are switched on, the seat occupant experiences a draft, particularly when the ventilation device is initially operated at the maximum level and is then slowly switched down to a predetermined value.
One object of the present invention is to develop an air supply mechanism for a vehicle seat and a method for the operation thereof in such a manner that, even immediately after the air supply mechanism is switched on, the seat occupant does not experience any draft.
These and other objects and advantages are achieved by the air supply mechanism for a vehicle seat according to the invention, in which a heating element is preconditioned before the air supply mechanism for a vehicle seat is switched on. As a result, the temperature of the discharging air is pleasantly controlled immediately when the air supply mechanism is switched on, and the vehicle occupant feels a pleasant heat. No experience of a draft occurs.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.